UPS Battery Preventative Maintenance

by | Data Centers


There is a direct link between maximizing the availability of mission-critical operations and UPS and battery Preventive Maintenance. Previously, the demand for service was driven by the need to protect the UPS investment. The price of the UPS system, depending on the load of the equipment, can be one of greatest expenditures in a data center. Hence, protecting the investments by prolonging equipment life through preventative maintenance makes practical business sense. In addition to protecting the asset investment, and often times most important, is ensuring up-time. The cost of downtime in many cases grossly out ways the cost of the asset or maintaining it properly.


Typical UPS and battery service contracts include scheduled preventive maintenance visits, either semi-annual or quarterly, guaranteed 4 hour emergency service response times, and specific replacement parts. All of which drastically lower the mean time between failure and the mean time between failure and repair. Today’s top-tier 3rd party service providers service all of the major OEMs, Liebert, MGE, APC, and Powerware maintaining parts inventories for expedited repair.


Like anything else that can be purchased in bulk, greater quantities of equipment cost less per unit to maintain. Partnering with a service firm that has a national presence with in-house field service engineers provides data center owners with multiple locations the best possible pricing and business continuity through consistent and defined standards.


Suggested Annual Maintenance Tasks:

  • Thermal scan equipment for excessive heat
  • Verify proper load sharing among modules
  • Calibrate equipment AC, DC, Voltage, Amperage and frequency metering
  • Test UPS switch gear transfer logic
  • Exercise the operation of the UPS circuit breakers and contractors, if applicable
  • Electrically verify rectifier DC float, recharge and equalize voltage
  • Electrically verify rectifier DC ripple is within parameters
  • Perform control logic calibration per operational specifications
  • Verify and adjust system load share load share for correct levels
  • Electrically verify static switch gate drive circuits, voltage redundancy transfer and transfer levels
  • Check torque of mechanical and electrical connections
  • Perform operational integrity verification, transfers and battery discharge
  • Perform and verify correct UPS system input fail operations (if approved by customer)

Suggested Semi-Annual Maintenance Tasks:

  • Inspect major magnetics for signs of excessive heat or deterioration within the windings, winding insulators and core laminations and mounting hardware
  • Verify major magnetic 1st and 2nd stage over temperature alarms functions
  • Visually and electrically inspect rectifier major power assemblies
  • Visually and electrically inspect inverter major power assemblies
  • Measure and record AC input filter bank amperage and capacitance
  • Measure and record AC output filter bank amperage and capacitance
  • Visually and electrically inspect logic major assemblies
  • Electrically verify control logic power supply potentials
  • Electrically verify critical logic control and power signals
  • Electrically verify critical power output waveforms are within parameters
  • Visually inspect power and control wiring for damage, worn insulation and signs of excessive heat or arcing
  • Check power and control lugs and connections
  • Visually inspect UPS switch gear components for signs of damage
  • Visually inspect UPS switch gear circuit breakers and contacts (exercise if applicable)
  • Electrically verify UPS switch gear logic power supply potentials
  • Visually inspect UPS switch gear power and control wiring for damage, worn insulation and signs of excessive heat or arcing

Suggested Quarterly Maintenance Tasks:

  • Inspect the environment, general room condition (cleanliness, security, access to equipment)
  • Check for proper air movement, in and around the equipment
  • Check air filters: (replace if necessary)
  • identify any abnormal noise
  • Inspect Instruments and record equipment readings
  • Verify status indicating lights are functional
  • Verify alarm and system status indication lights are displaying correct equipment operational status
  • Inspect AC input filter capacitors for open fuses, swelling and leakage
  • Inspect DC filter capacitors for open fuses, swelling and leakage
  • Inspect AC output filter capacitors for open fuses, swelling and leakage
  • Inspect DC bleeder resistors
  • Verify automatic transfer systems are enabled
  • Verify remote status panel / building management systems correct operational status

Following these practices should ensure consistent performance and up-time of this vital piece of equipment in your data center.

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